Field of the Invention
The present invention relates to devices for damping tarps and other flexible sheet materials.
Related Art
The current invention provides as damp for flexible sheet material such as a tarp or flexible sheet plastic material used for covering items such as pickup truck beds, flatbed truck beds, or any items needing covering, such as piles of materials needing protection from the elements or holes in items that need covering, such as holes in building roofs. For purposes of this application, all such flexible sheet materials will be referred to as tarps. As usually used, a tarp is a strong, flexible, water-resistant sheet material that provides protection from the elements and comes in various material types and thickness. For example, a tarp must be constructed from polyethylene, canvas, or vinyl, and the thickness can range from regular duty to heavy duty. Many tarps have grommets which are normally comprised of rings inserted into holes in the tams along the sides and the corners. The grommets provide attachment points for ropes and bungee cords, which allow the tarps to be placed over items requiring protection from the elements and to be tied down, which effectively protect such covered items against weather damage. Tarps are also commonly used to cover pickup truck beds or trailer beds to cover loads of material being carried by such trucks or trailers to keep such materials from blowing from the truck or trailer beds while traveling on highways. Tarps are commonly used to cover loads of brush or other trash being transported to disposal sites. When grommets are provided in the tarp, they can be used to secure the tarp over the item needing protection or over the load needing protection and restraint. Tarps are also functional without using or without having grommets. For example, a tarp can be used to cover a load of material in a truck by covering the material with a tarp, and securing the tarp by means of ropes that are tied to the sides of the truck, and secured tightly over the tarp.
However, there are a number of problems with tying down a tarp by using grommets and or ropes. First, the grommets are not necessarily present in the optimal location for tying down the tarp. Second, the grommets are not necessarily strong enough to withstand the strain caused by the tension of the rope, which can result in the premature tearing of the fabric surrounding the grommet. Third, if the grommet breaks, then it is necessary to replace the grommet, which is difficult without the proper tools.
Additionally, or tarps not provided with grommets, it may be difficult and time consuming to use rope to tie down the tarp. When using rope to secure a tarp on or over a truck bed, several problems can arise. First, the tarp will not be evenly secured over the truck bed unless a lot of rope is used, and the rope is secured in a fastidious manner. Second, securing the rope over the tarp in this manner takes unnecessary time because the rope must be secured tightly over the load after the load has been placed in the truck bed, and the rope must be removed when removing the load from the truck bed.
The prior art has addressed these shortcomings in various ways, including piercing and clamping. In U.S. Pat. No. 7,189,024, a connector assembly allows a rope to be attached to a tarp by piercing the tarp and screwing the opposing ends of the connector members to each other. Each connector member comprises a mostly flat surface with multiple bumps on the surface. The bumps keep the connector members from moving in relation to each other, and the piercing mechanism keeps the two connecting members attached to each other. The bumps also provide a stronger grip on the tarp being held between the two connector members. In U.S. Pat. No. 9,267,517, a sheet material clamp uses an actuating screw in combination with an upper and lower damping jaw in which the clamping jaws are designed to clasp together and maintain a grip on the sheet material. The clamping as are formed of a rigid material and each have an uneven surface to prevent the material in between the clamping jaws from slipping from between the jaws.
There are deficiencies with both of these prior art references. Most importantly, neither prior art reference addresses the problem of tying down a tarp over a truck bed. In addition, both prior art references are concerned with fixing problems with grommets, but fail in even this respect. Piercing the material of a tarp has the effect of creating holes in the material when no holes are necessary and is likely to shorten the lifetime of the tarp. Although this might secure the tarp initially, this method provides little advantage over using grommets, which provide the very function that this prior art is hoping to achieve. Clamping a tarp does not have this disadvantage of creating holes in the material of the tarp, but does have the disadvantage of ripping and tearing the material of the tarp because of the shape of the clamping jaws and their uneven surface.
Based on the foregoing, there exists a need for a tarp clamping, device that does not rely on ropes or grommets, or on piercing the material of the tarp. Furthermore, this new device must use as clamping mechanism that does not rip or tear the material of the tarp by using clamping jaws with an uneven surface. Therefore, there is a need for a tarp clamping device that can clamp the material of the tarp by evenly distributing pressure from the clamping jaws while still maintaining a firm grip on the tarp.